In recent years, the development of heterogeneous platinum-metal catalysts has advanced markedly. Efforts have been directed toward producing effective catalysts for reducing atmospheric pollution by industrial processes as well as atmospheric pollution by exhaust gases from internal combustion engines.
Many processes have been suggested for making catalysts containing platinum metals. However, these catalysts are frequently thermally and chemically unstable in use and the preparation of a catalyst and placing it in a form suitable for use in industrial or automotive applications is often an extended, multi-stage operation. A continuing need therefore exists for more efficient methods of preparing stable catalysts than have heretofore been available.